INFLUENCE OF Ce ION IMPLANTATION ON OXIDATION BEHAVIOR OF Ni20Cr ALLOY
(State Key Laboratory for Corrosion and Protection; Institute of Corrosion and Protection of Metals; Chinese Academy of Sciences; Shenyang 110015)
Abstract: The ion implantation of 2×1016 , 5×1016 and 1×1017 Ce+/cm2 to Ni20Cr alloy can significantly decrease its oxidation rate at 1 000 ℃ and 1 100 ℃, and improve the adhesion of oxide scales. The influence of Ce ion implantation on the binding energy of alloying elements has been studied by Ion Microprobe Miss Analyzer (IMMA). The binding energy of Cr+ in the implanted layer of the alloy decreases, which promotes the protective Cr2O3 to form quickly during the initial oxidation stage. However the binding energies of Cr+ and Ni+ in the oxide scales increase, and the outward diffusion of Cr3+ and Ni2+ through the oxide scales is suppressed. This result may be related to changing the concentration of defects due to Ce ion implantation. After cyclic oxidation at 1 000 ℃ for 270 times, the beneficial effect of Ce on the resistance to oxidation is still obvious.
Key words: oxidation cerium Ni20Cr alloy ion implantation